~1934-5 Large (Oversize) Marine Green VACUUM-FIL

 In 1933 Sheaffer created a sub-brand they called VACUUM-FIL. VACUUM-FIL was intended for the initial release of the Sheaffer version of vacuum filler. The first Sheaffer Balance with a vacuum filler appeared in the 1935 catalog. VACUUM-FIL renamed the WASP Pen Co in 1936.

This is the largest VACUUM-FIL / WASP pen made; collectors call it OS or Oversize. This is probably a second generation pen. The first generation pens have fat, 1/8" (3.175 mm) filler rods. The second generation pens have the same 5/64" (2.07 mm) rods used on the later Balance pens. I have replace the original rod with a black oxide coated stainless steel rod. The original was celluloid covered carbon steel. Those often fail when moisture gets beneath the cover and the rod rusts. This stainless rod will last the life of the pen.

I've also replaced the packing unit at the tail end of the pen. This bit is threaded into the pen and has threads extending from the end of the pen to take the blind cap. Internally it holds the seal around the filler rod. These seals are modern synthetic. The only maintenance is an occasional application of 100% silicone grease on the filler rod.

The nib is soft, bouncy, wet and an amazing writer. I hesitate to describe it as semi-flex because these nibs are 12 karat gold and quite thin. They provide lovely line variation under normal writing pressure but should never be pushed like a truly flexible nib.

The peak of the clip has some pitting to the plating. The cap band and clip ball have areas of plating loss. The transparent barrel has darkened a bit from its original pale green. The celluloid has no damage at all.

Length
Capped - 128 mm (5.1”)
Uncapped - 119 mm (4.7”)
Posted - 150 mm (6”).
Diameter
Cap - 13.3 mm (0.53”)
Barrel - 11.5 mm (0.44”)

Filler
Vacuum-Fil

Nib
soft fine